1. Field of the Invention
The present invention relates to a hologram medium manufacturing method, a master hologram medium manufacturing method, a recording medium, and a hologram medium manufacturing apparatus.
2. Description of the Related Art
As a leading next-generation optical memory, a so-called microhologram system described in “Microholographic multilayer optical disk data storage”, R. R. McLeod et al., Appl. Opt., Vol. 44, 2005, p 3197 (hereinafter, referred to as Non-patent Document 1) is proposed.
In this system, when information is recorded, coherent recording light beams are simultaneously emitted to a recording medium from a front and back surface side thereof using two objective lenses so that the recording light beams are focused on the same position, to thereby record a minute hologram.
Further, the light focus positions of the recording light beams are three-dimensionally changed in the recording medium, to thereby three-dimensionally record a minute hologram in the recording medium.
For reproduction of the information, reference light is focused on the recording medium through the objective lens to detect reproduction light generated from the recorded minute hologram.
According to the above-mentioned system, information is three-dimensionally recorded in the recording medium in a bit manner. Therefore, a larger increase in storage capacity than an optical disk in related art is expected (see, for example, Non-patent Document 1).